We have a few things available for the 800R XP. We have a single pipe, Y pipe, and muffler for trail riding. Each of these will bolt on the stock components as well as with each other. There is no need for any jetting changes when you install one or a combination of any of the exhaust parts. The pipe is available for sea level 0-3000' or high attitude above 3000' please specify when ordering. The expected horsepower gains with the single pipe is 3-4 and the Y-Pipe is 3. The muffler is a weight savings and will sound like the stock muffler. All parts are available either ceramic coated or high temperature black paint. We can machine the stock head to have Crank Shop domes that will produce 2-3HP on top end and 4HP in mid range. The trail mod kit produces 173HP @ 8200 RPM's and includes; trail porting customer supplied cylinders & raves, single pipe, y-pipe, v-force 3 reeds, and machine the stock head for our domes. The kit is available either high temperature black paint or ceramic coated. The modified race motors are producing 180HP @ 8400 RPM's. The HP figures are based on dynoing with the 600RS TMX carbs CNC taper bored. The stock 800R carbs bring down the horsepower 7-8 horse when used with the race package. The labor to disassemble, clean, and assemble the motor is NOT included in the package price. The twin pipes are for a race motor ONLY, they do not work for a trail motor.